From 2d4f9ad89cb7e79c1f90983bf4898a5f4e3c7457 Mon Sep 17 00:00:00 2001
From: Ben Gamari <ben@smart-cactus.org>
Date: Thu, 7 Nov 2019 14:31:15 -0500
Subject: Ensure that coreView/tcView are able to inline

Previously an import cycle between Type and TyCoRep meant that several
functions in TyCoRep ended up SOURCE import coreView. This is quite
unfortunate as coreView is intended to be fused into a larger pattern
match and not incur an extra call.

Fix this with a bit of restructuring:

 * Move the functions in `TyCoRep` which depend upon things in `Type`
   into `Type`
 * Fold contents of `Kind` into `Type` and turn `Kind` into a simple
   wrapper re-exporting kind-ish things from `Type`
 * Clean up the redundant imports that popped up as a result

Closes #17441.

Metric Decrease:
    T4334
---
 compiler/types/TyCoRep.hs | 87 -----------------------------------------------
 1 file changed, 87 deletions(-)

(limited to 'compiler/types/TyCoRep.hs')

diff --git a/compiler/types/TyCoRep.hs b/compiler/types/TyCoRep.hs
index 065efcd417..be2f74c731 100644
--- a/compiler/types/TyCoRep.hs
+++ b/compiler/types/TyCoRep.hs
@@ -14,8 +14,6 @@ Note [The Type-related module hierarchy]
   TyCoSubst imports TyCoRep, TyCoFVs, TyCoPpr
   TyCoTidy imports TyCoRep, TyCoFVs
   TysPrim  imports TyCoRep ( including mkTyConTy )
-  Kind     imports TysPrim ( mainly for primitive kinds )
-  Type     imports Kind
   Coercion imports Type
 -}
 
@@ -52,12 +50,6 @@ module TyCoRep (
         mkForAllTy, mkForAllTys,
         mkPiTy, mkPiTys,
 
-        kindRep_maybe, kindRep,
-        isLiftedTypeKind, isUnliftedTypeKind,
-        isLiftedRuntimeRep, isUnliftedRuntimeRep,
-        isRuntimeRepTy, isRuntimeRepVar,
-        sameVis,
-
         -- * Functions over binders
         TyCoBinder(..), TyCoVarBinder, TyBinder,
         binderVar, binderVars, binderType, binderArgFlag,
@@ -77,7 +69,6 @@ module TyCoRep (
 
 import GhcPrelude
 
-import {-# SOURCE #-} Type( coreView )
 import {-# SOURCE #-} TyCoPpr ( pprType, pprCo, pprTyLit )
 
    -- Transitively pulls in a LOT of stuff, better to break the loop
@@ -94,7 +85,6 @@ import CoAxiom
 
 -- others
 import BasicTypes ( LeftOrRight(..), pickLR )
-import PrelNames
 import Outputable
 import FastString
 import Util
@@ -960,83 +950,6 @@ mkPiTys tbs ty = foldr mkPiTy ty tbs
 mkTyConTy :: TyCon -> Type
 mkTyConTy tycon = TyConApp tycon []
 
-{-
-Some basic functions, put here to break loops eg with the pretty printer
--}
-
--- | Extract the RuntimeRep classifier of a type from its kind. For example,
--- @kindRep * = LiftedRep@; Panics if this is not possible.
--- Treats * and Constraint as the same
-kindRep :: HasDebugCallStack => Kind -> Type
-kindRep k = case kindRep_maybe k of
-              Just r  -> r
-              Nothing -> pprPanic "kindRep" (ppr k)
-
--- | Given a kind (TYPE rr), extract its RuntimeRep classifier rr.
--- For example, @kindRep_maybe * = Just LiftedRep@
--- Returns 'Nothing' if the kind is not of form (TYPE rr)
--- Treats * and Constraint as the same
-kindRep_maybe :: HasDebugCallStack => Kind -> Maybe Type
-kindRep_maybe kind
-  | Just kind' <- coreView kind = kindRep_maybe kind'
-  | TyConApp tc [arg] <- kind
-  , tc `hasKey` tYPETyConKey    = Just arg
-  | otherwise                   = Nothing
-
--- | This version considers Constraint to be the same as *. Returns True
--- if the argument is equivalent to Type/Constraint and False otherwise.
--- See Note [Kind Constraint and kind Type]
-isLiftedTypeKind :: Kind -> Bool
-isLiftedTypeKind kind
-  = case kindRep_maybe kind of
-      Just rep -> isLiftedRuntimeRep rep
-      Nothing  -> False
-
--- | Returns True if the kind classifies unlifted types and False otherwise.
--- Note that this returns False for levity-polymorphic kinds, which may
--- be specialized to a kind that classifies unlifted types.
-isUnliftedTypeKind :: Kind -> Bool
-isUnliftedTypeKind kind
-  = case kindRep_maybe kind of
-      Just rep -> isUnliftedRuntimeRep rep
-      Nothing  -> False
-
-isLiftedRuntimeRep :: Type -> Bool
--- isLiftedRuntimeRep is true of LiftedRep :: RuntimeRep
--- False of type variables (a :: RuntimeRep)
---   and of other reps e.g. (IntRep :: RuntimeRep)
-isLiftedRuntimeRep rep
-  | Just rep' <- coreView rep          = isLiftedRuntimeRep rep'
-  | TyConApp rr_tc args <- rep
-  , rr_tc `hasKey` liftedRepDataConKey = ASSERT( null args ) True
-  | otherwise                          = False
-
-isUnliftedRuntimeRep :: Type -> Bool
--- True of definitely-unlifted RuntimeReps
--- False of           (LiftedRep :: RuntimeRep)
---   and of variables (a :: RuntimeRep)
-isUnliftedRuntimeRep rep
-  | Just rep' <- coreView rep = isUnliftedRuntimeRep rep'
-  | TyConApp rr_tc _ <- rep   -- NB: args might be non-empty
-                              --     e.g. TupleRep [r1, .., rn]
-  = isPromotedDataCon rr_tc && not (rr_tc `hasKey` liftedRepDataConKey)
-        -- Avoid searching all the unlifted RuntimeRep type cons
-        -- In the RuntimeRep data type, only LiftedRep is lifted
-        -- But be careful of type families (F tys) :: RuntimeRep
-  | otherwise {- Variables, applications -}
-  = False
-
--- | Is this the type 'RuntimeRep'?
-isRuntimeRepTy :: Type -> Bool
-isRuntimeRepTy ty | Just ty' <- coreView ty = isRuntimeRepTy ty'
-isRuntimeRepTy (TyConApp tc args)
-  | tc `hasKey` runtimeRepTyConKey = ASSERT( null args ) True
-isRuntimeRepTy _ = False
-
--- | Is a tyvar of type 'RuntimeRep'?
-isRuntimeRepVar :: TyVar -> Bool
-isRuntimeRepVar = isRuntimeRepTy . tyVarKind
-
 {-
 %************************************************************************
 %*                                                                      *
-- 
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